We describe a cw Kerr-lens mode-locked ${\text{Cr}}^{2+}$ :ZnSe laser pumped by a 1800 nm thulium fiber laser. The astigmatically compensated asymmetric x cavity contained a 2.4-mm-long ${\text{Cr}}^{2+}$ :ZnSe sample with a pump absorption coefficient of $11.6{\text{cm}}^{-1}$ and was operated with a 1% output coupler. The dispersion compensation was achieved by using a ${\text{MgF}}_2$ prism pair. During Kerr-lens mode-locked operation, we could generate 95 fs pulses at a pulse repetition rate of 94.3 MHz and with 40 mW of output power. The center wavelength of the pulses was 2420 nm. The pulses had a spectral width of 69 nm and a time–bandwidth product of 0.335, which is close to the transform limit for hyperbolic secant pulses.